What is the primary purpose of a surge tank in a pumping system?

• A. to prevent water hammer
• B. to store water
• C. to regulate pressure
• D. to cool the fluid

Answer: (A)

Transient pressure control is what a surge tank provides in a pumping system. When a pump starts abruptly, a valve closes suddenly, or flow changes direction, the moving water has momentum that creates a pressure spike known as water hammer. The surge tank adds extra volume and an energy‑absorbing cushion (often an air gap) so the sudden change in flow doesn’t translate into a sharp, dangerous pressure rise throughout the piping. This dampens the pressure wave, protecting pipes, fittings, and equipment from damage and reducing noisy, damaging surges.

Storing water isn’t the primary purpose—the tank is not just a reservoir. Regulating pressure can be a secondary effect, but it’s the surge absorption that’s central. Cooling the fluid isn’t related to why a surge tank is used.